JPH0830910B2 - Colorant for electrophotographic recording method - Google Patents

Description

The present invention relates to a novel colorant for electrophotographic recording which comprises a mixed crystal of pigments based on substituted perylenetetracarboxylic acid-diphenylimides.

The problem underlying the present invention is to find electrophotographic recording colorants which have improved properties and are composed of no more than two components for use in electrophotographic recording.

In electrophotographic recording, a "latent charge image" occurs, for example, on the photoconductor drum. This is achieved by charging the photoconductor drum by corona discharge and by subsequent imagewise exposure of the electrostatically charged surface of the photoconductor drum, where earth is present at the exposed locations. The substrate is discharged from the charge. The "latent charge image" thus formed is subsequently developed by the application of a toner.

In a subsequent step the toner is transferred from the photoconductor drum onto, for example, paper, fiber material, foil or synthetic resin and fixed there, for example by pressing, irradiation, heating or solvent action. The photoconductor used is subsequently cleaned and used in a new recording method.

A great number of patent specifications describe the optimum state of the toner, in particular the effect of the toner binder (resin / resin component or wax / wax component change), charge control agent or other The effects of additives or carriers (in the case of a two-component developer) and magnetic pigments (in the case of a one-component developer) have been tested (US Pat. No. 2,221,776).

A measure of toner quality is its specific charge Q / M (charge amount per unit mass).

From the patent literature it is known to use a large number of organic pigments and dyes of various classes for coloring colored copying or printing toners, for example monoazo-, disazo-, benzidine-, copper phthalocyanine- and perylenetetracarboxylic acid derivatives. Is.

Laked or unlaked monoazo pigments such as C.I. Pigment Red 48 (1586
5) Among them, perylene tetracarboxylic acid derivatives such as C
It has been demonstrated that eye pigment red 149 (71137) is suitable for making red toner. In this case, the use of the high-grade C.I. Pigment Red 149 is advantageous not only for its better robustness, but also for its good triboelectric behavior, especially in the red toner.

Further improvement of the toner is described in JP-A-34-219756 and JP-A-34-220750. The first cited Japanese Patent Laid-Open Publication, for example, see C.I.
A red toner is described which contains a mixture of red 149 and C.I. pigment red 222 to provide the desired toner properties. (The pigment mixture in the toner is only in the pigment mixture in the toner binder). According to the description of the second Japanese Patent Laid-Open Publication No. Sho-Shi Pigment Red 149 and Sea-I Pigment Red 177.
A similar favorable effect is achieved by using a mixture consisting of (65300). According to JP-A-34-197049,
To improve triboelectric charging, certain substituted perylene tetracarboxylic acid-derivatives are added to the toner. Whether such additions can outperform the C.I. Pigment Red 149 standard remains unsolved, but such additions do not prevent the combined toner-blend from at least one component. It has certain problems that must be broadened only, and as a result pigment compatibility, mixing problems and different shades must be taken into account.

A recent development is the use of mixed crystals of organic pigments when making electrographic ethoners. For example, in European Patent Application Publication No. 0042816, "pigment blend" relating to toner in the field of electrography.
The suitability of is described. In this case, "pigment mix" means sufficient grinding of a pigment consisting of two completely different classes of pigments (eg C.I. Pigment-Yellow 110 (isoindrenine-pigment) and perylenetetracarboxylic imide). It means the mixed crystal obtained by.

Surprisingly, on the other hand, the present inventor used two components, a toner binder (polymer) and a pigment (mixed crystal), to produce a toner that is suitable and highly effective for the purposes discussed. Of the system but without the need for a modifier or only a limited amount of additional charge control agent-whereas the colored mixed crystal additionally functions as a charge control agent. This is because it shows a great simplification as compared with a known toner composed of three or more components-from the viewpoint that a mixed crystal based on a specific perylenetetracarboxylic acid-diphenylimide is used. Have been found to be outstandingly suitable as colorants for electrophotographic recording.

The mixed crystals used according to the invention surprisingly also have more pronounced triboelectric properties than the C.I. Pigmented Red 149.

The subject of the present invention is therefore the compounds 99-70 of the general formula I
And 1 to 30 parts of the compound of the following general formula II (R in general formula II represents a C ₁ -C ₄ -alkyl group), a colorant for electrostatic recording, which is especially used for electrophotographic copying of original and electronic engineering. Another method is to use said colorant in the manufacture of a toner used for printing information stored optically or magnetically.

The mixed crystal pigments and / or their preparation which form the basis of the colorants according to the invention are described in German patent applications P3436206.1 and P343.
6208.8.

In the case of the colorants according to the invention, in the case of the complete omission of the addition of a separate charge control agent which has to be added as a third component in the production of the toner, problems which may occur during the addition of the charge control agent, for example in the toner. In principle, inhomogeneous dispersion of the charge control agent or gradual migration of the charge control agent from the toner can be avoided. If the addition of separate charge control agents cannot be dispensed with altogether, then the problems can still be reduced.

The degree of electrostatic charging of the toner using the mixed crystal composed of the compounds of the general formulas (I) and (II) in the above mixing ratio is the same under the standard system (for example, the same dispersion time, the same particle size). Distribution, same grain shape) at 23 ° C and 50% relative air humidity.

Activation of the toner in the two-component developer is carried out by using the toner as carrier (3 parts of toner vs. 97 parts of carrier).
It is carried out by mixing in a roll mill (150 rpm) for 1 minute.

The present invention is illustrated by the following examples, which should not be construed as limiting the invention. The stated parts are parts by weight.

Example 1 Pigment (the above general formulas I and II (R
= C ₂ H ₅ ) mixed crystal) 5 parts by Werner & Pfle
Toner binder ( ^(R) Dialec S 309 from Diamond Shamrock ⁾ using a kneader from iderer (Stuttgart) for 90 minutes.
-Styrene-methacryl-copolymer-) dispersed in 95 parts. Subsequently, it is ground with 100 LU of universal laboratory mill from ALPINE (Augsburg), and then centrifugal shifter 100 from ALPINE.
Classify with MZR. Carrier composed of magnetite particles of 50-200 μm size coated with styrene-methacrylate 90:10 in a particle fraction of 4-25 μm-PLASMA MATERIALS INC.
It is activated by the company's type 90μm Xerographic E-Carrier. The triboelectric charging property is measured by the usual Q / M measurement standard (vgl.JH Dessauer, HEClark “Xero
graphy and related Processes '', Focal Press, NY19
65, p. 289).

 The Q / M-value is measured as -18.9 μC / g.

Example 2 The procedure is as described in Example 1, except that the pigment is used in a quantity ratio of approx.
This is carried out with the difference that a mixed crystal of the compounds of the above-mentioned general formulas I and II (R = C ₂ H ₅ ) in 97: 3 is used.

 The Q / M-value is measured as -17.2 μC / g.

Example 3 The procedure is as described in Example 1, with the exception that the pigment
It is carried out with the difference that Eye Pigment Red 149 (prepared according to Example 1 of DE 1067157) is used.

 The Q / M-value is measured as -7.1 μC / g.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Helmut Trestel, Federal Republic of Germany, Königs Hyuyustein / Taunus, Am Ertwershutin, 44 (56) Reference JP-A-59-220750 (JP, A) ) JP-A 61-34554 (JP, A) JP-A 59-219756 (JP, A) JP-A 59-197049 (JP, A)

Claims (2)

[Claims] 1. 99 to 70 parts of a compound represented by the following general formula I and 1 to 30 parts of a compound represented by the following general formula II (R in general formula II represents a C ₁ -C ₄ -alkyl group), which is a colorant for electrophotographic recording. 2. The following general formula for the production of toners or developers used for electrophotographic reproduction of originals and for printing information stored electronically, optically or magnetically. 99 to 70 parts of the compound represented by I and 1 to 30 parts of the compound represented by the following general formula II (In the general formula II, R means a C ₁ -C ₄ -alkyl group).